Explanation

• Sputnik-1 was launched by the USSR (Soviet Union) on 4 October 1957.
• It was the world's first artificial satellite, beginning of the Space Age.
• It started the Space Race between the Soviet Union and the United States.
• Launch Site: Baikonur Cosmodrome, Kazakhstan
• Weight: 83.6 kg
• Orbital Period: About 96 minutes

Last verified on 09-03-2026

Explanation

• Fission is the process in which a heavy atomic nucleus splits into two or more smaller nuclei, releasing a large amount of energy.
• It usually occurs when a heavy nucleus, such as Uranium-235 or Plutonium-239, absorbs a neutron.
• The process also releases additional neutrons, which can start a chain reaction.
• Nuclear fission is used in nuclear power plants and atomic bombs.

Last verified on 07-07-2026

Explanation

• Boiling point of water: 100°C
• Freezing point of water: 0°C
• Standard atmospheric pressure: 1 atm (760 mmHg)
• 0°C = 32°F
• 100°C = 212°F

Last verified on 06-07-2026

Explanation

• Zero error is a Systematic error because it causes a consistent error in every measurement.
• It occurs when an instrument does not read zero even when no quantity is being measured.
• The same error is repeated in all readings unless corrected.
• Zero error may be positive or negative.
• It can be corrected by applying a zero correction.

Last verified on 06-07-2026

Explanation

• Convex lenses are known as Converging lenses.
• Because they bring parallel light rays to a single focal point.
• A convex lens is thicker at the center and thinner at the edges.
• It forms real and inverted images when the object is beyond the focal length.
• It can also produce a virtual, erect, and magnified image when the object is placed within the focal length.

Additional information:

• Concave lens is also called a diverging lens.

Last verified on 11-03-2026